Many tooth fillings nowadays use what are known as visible light-curable dental composite materials. The composite materials typically comprise a plastic material, a filler and a visible light sensitive compound which will cause the material to cure upon exposure to visible light.
Typically, a tooth is filled with the dental composite material in viscous paste form. The filling is then worked by the dentist to the desired configuration. Subsequently, the filling is cured by the dentist by means of a special light which emits visible light.
However, it has now been discovered that the dental composite material can cure prematurely because of radiation emitted by the dental lamp which generally illuminates patients' mouths during dental procedures. It has now been discovered that the premature curing is brought about because the dental composite material is sensitive to radiation at the lower end of the visible part of the electromagnetic spectrum, for example, in the range from 400 to 520 nm, preferably 450 to 470 nm, most preferably about 460 nm, and the dental lamp emits radiation in this wavelength range.
Dentists have been attempting to avoid this problem by turning off the dental lamp or turning it away while working with dental composite materials. However, this is unsatisfactory because the dentist then has insufficient light for correct working practices.